Русские вцелом к полякам близки, а не только северные. Ведь не только древние словене вышли из, кхм, более западных областей, но так же и вятичи с радимичами.
Балановский, помнится, писал, что восточных славян + поляки вообще сложно между собой различить.
По аутосомам получается, что в целом к полякам близки и неразличимы с ними как раз южно-средние русские, а северные стоят особняком далеко от поляков. Вот сравнение рязанских русских с другими и северных:
Distance to: Russian_Ryazan
0.01182092 Russian_Kursk
0.01260827 Russian_Tver
0.01309084 Ukrainian_Dnipro
0.01344767 Russian_Orel
0.01738041 Russian_Voronez
0.01857005 Ukrainian_Rivne
0.01934512 Russian_Yaroslavl
0.01937826 Ukrainian_Chernihiv
0.01958805 Russian_Kaluga
0.01992937 Cossack_Ukrainian
0.02019712 Russian_Belgorod
0.02119121 Ukrainian_Zhytomyr
0.02185665 Ukrainian_Sumy
0.02268283 Russian_Smolensk
0.02361744 Belarusian
0.02462955 Russian_Pskov
0.02500927 Moksha
0.02627707 Polish
0.02675007 Moldovan_o
0.02799281 Lithuanian_PA
0.03005283 Russian_Kostroma
0.03125010 Ukrainian_Lviv
0.03158572 Cossack_Kuban
0.03187338 Erzya
0.03221773 Lithuanian_VA
0.03393753 Polish_Kashubian
0.03421019 Estonian
0.03457248 Ukrainian_Zakarpattia
0.03572993 Lithuanian_RA
0.03605689 Polish_Silesian
0.03609668 Slovakian
0.03786346 Sorb_Niederlausitz
0.03926540 Lithuanian_VZ
0.03982618 Ingrian
0.04175668 Russian_Krasnoborsky
0.04282038 Czech
0.04350246 Lithuanian_SZ
0.04543345 Latvian
0.04605751 Finnish_Southwest
0.04611296 Lithuanian_PZ
0.04683541 Finnish_Southeast
0.04702102 Finnish_Central
0.04952720 Hungarian
0.05048149 Karelian
0.05121179 German_East
0.05147457 Vepsian
0.05221689 Slovenian
0.05269679 Croatian
0.05581443 German_Hamburg
0.05607240 Finnish_East
0.05660037 Finnish_North
0.05663125 Swedish
0.06042476 Russian_Pinega
0.06109628 Bosnian
0.06171511 Austrian
0.06186704 German_Erlangen
0.06320418 Russian_Pinezhsky
0.06434811 Moldovan
0.06675544 German
0.06875166 Danish
0.06988913 Norwegian
0.07258724 Icelandic
0.07324996 Serbian
0.07327682 Dutch
0.07344838 Afrikaner
0.07557372 Montenegrin
0.07558050 Shetlandic
0.07649794 Orcadian
0.07772206 Scottish
0.07963269 Welsh
0.07965692 English
0.08016593 French_Seine-Maritime
0.08057931 Russian_Leshukonsky
0.08061625 BelgianA
0.08099440 Irish
0.08254304 Tatar_Mishar
0.08256320 English_Cornwall
0.08271741 Romanian
0.08310286 French_Brittany
0.08369795 French_Alsace
0.08532480 French_Nord
0.08545419 BelgianB
0.08742269 French_Pas-de-Calais
0.08774257 Macedonian
0.08921892 Swiss_German
0.09003391 BelgianC
0.09046088 Bulgarian
0.09316355 French_Paris
0.09433578 Turkish_Deliorman
0.09471143 Komi
0.09761555 Gagauz
0.09963889 Italian_Northeast
0.10040256 French_Occitanie
0.10147138 Greek_East_Macedonia_and_Thrace
0.10149767 French_Auvergne
0.10301722 Swiss_French
0.10518630 Italian_Friuli_Venezia_Giulia_Sappada
0.10546944 French_Provence
0.10806854 Italian_Aosta_Valley
0.11212925 Italian_Trentino_Alto_Adige
Distance to: Russian_Krasnoborsky
0.01520106 Vepsian
0.01536503 Russian_Kostroma
0.01747470 Karelian
0.01924859 Erzya
0.02272015 Russian_Pinega
0.02347318 Moksha
0.02383299 Ingrian
0.02543310 Russian_Pinezhsky
0.02604835 Finnish_Central
0.02794334 Finnish_North
0.02958723 Finnish_East
0.03520812 Finnish_Southeast
0.03666077 Russian_Yaroslavl
0.03676751 Russian_Tver
0.03750439 Finnish_Southwest
0.03863403 Cossack_Kuban
0.04175668 Russian_Ryazan
0.04289877 Russian_Leshukonsky
0.04640149 Russian_Kursk
0.04690879 Estonian
0.04809512 Russian_Kaluga
0.04903100 Russian_Orel
0.04946763 Russian_Pskov
0.04951008 Ukrainian_Dnipro
0.05085540 Cossack_Ukrainian
0.05224881 Russian_Voronez
0.05568887 Belarusian
0.05599463 Russian_Belgorod
0.05660227 Ukrainian_Chernihiv
0.05683746 Russian_Smolensk
0.05687907 Ukrainian_Rivne
0.05757600 Tatar_Mishar
0.05763310 Ukrainian_Sumy
0.05764183 Lithuanian_PA
0.05884990 Lithuanian_VA
0.05950073 Ukrainian_Zhytomyr
0.05989153 Komi
0.06042914 Lithuanian_RA
0.06111176 Moldovan_o
0.06193400 Polish
0.06199484 Lithuanian_VZ
0.06227049 Latvian
0.06365250 Lithuanian_SZ
0.06428886 Lithuanian_PZ
0.06532382 Polish_Kashubian
0.06672514 Ukrainian_Lviv
0.06783938 Polish_Silesian
0.06878821 Ukrainian_Zakarpattia
0.06939791 Slovakian
0.07258775 Czech
0.07264454 Swedish
0.07402288 Sorb_Niederlausitz
0.07481621 Saami_Kola
0.07851901 Hungarian
0.08003797 German_Hamburg
0.08032705 German_East
0.08388540 Slovenian
0.08410536 Croatian
0.08523982 Norwegian
0.08760629 Danish
0.08827445 Tatar_Kazan
0.08842028 Icelandic
0.08845018 German_Erlangen
0.08881242 Austrian
0.09091954 German
0.09236222 Moldovan
0.09251764 Bosnian
0.09263421 Dutch
0.09267530 Afrikaner
0.09327665 Shetlandic
0.09380117 Orcadian
0.09497241 Scottish
0.09737825 Irish
0.09793381 English
0.09874071 Welsh
0.10146144 English_Cornwall
0.10242788 French_Brittany
0.10269827 BelgianA
0.10307260 Serbian
0.10352283 French_Seine-Maritime
0.10470892 Montenegrin
0.10703500 French_Alsace
0.10758502 French_Nord
0.10766183 BelgianB
0.10846507 French_Pas-de-Calais
0.10983233 Romanian
0.11031533 Turkish_Deliorman
0.11192180 Swiss_German
0.11194784 BelgianC
0.11200418 Besermyan
0.11477667 French_Paris
0.11718671 Macedonian
0.11724750 Bulgarian
0.12227418 French_Occitanie
0.12337402 Gagauz
0.12381198 French_Auvergne
0.12399509 Chuvash
0.12433632 Turkish_Rumeli
0.12462416 Saami
0.12535764 Italian_Northeast